Step 1: Brown the Sausage

1. Heat a large pot or Dutch oven over medium heat.
2. Add the Italian sausage, breaking it up with a wooden spoon as it cooks. Brown the sausage until fully cooked and no longer pink, about 5-7 minutes.
3. Remove the sausage from the pot and set it aside, leaving behind any rendered fat. If needed, add 1 tablespoon of olive oil to the pot.

Step 2: Sauté the Vegetables

1. In the same pot, add the chopped onion, carrots, and celery. Cook over medium heat for 4-5 minutes until softened and slightly golden.
2. Add the minced garlic and cook for another 30 seconds, stirring constantly to prevent burning.

Step 3: Build the Broth

1. Pour in the chicken broth, scraping the bottom of the pot to deglaze and release any browned bits.
2. Return the cooked sausage to the pot and stir to combine.
3. Add the dried Italian seasoning, crushed red pepper flakes (if using), and a pinch of salt and black pepper.

Step 4: Simmer the Soup

1. Bring the soup to a gentle boil, then reduce the heat to low.
2. Cover and simmer for 15-20 minutes to allow the flavors to meld.

Step 5: Add the Cream and Parmesan

1. Stir in the heavy cream and Parmesan cheese, mixing until the cheese is fully melted and the broth is creamy.
2. Taste and adjust the seasoning as needed.

Step 6: Add Optional Ingredients

1. If using spinach or kale, stir it into the soup and cook for 2-3 minutes until wilted.
2. For a heartier soup, add cooked pasta, rice, or diced potatoes at this stage and stir to combine.

Step 7: Garnish and Serve

1. Ladle the soup into bowls and garnish with extra Parmesan cheese and fresh parsley or basil.
2. Serve hot with crusty bread for dipping and enjoy!